Long-term therapy for angina pectoris is nowadays usually conducted with nitrates such as isosorbide-dinitrate or isosorbide-mononitrate, or with calcium antagonists.
Cutting short an acute angina pectoris attack proves considerably more difficult, since the named active substances only allow an immediate onset of action with i.v. administration. Furthermore, this can only be carried out by the doctor, who is in most cases not at hand when the angina pectoris attack occurs. A further disadvantage of parenteral treatment is that it can easily lead to postural hypotension in the case of calcium-antagonists on account of strong peripheral side-effects upon rapid absorption.
At present the sublingual or inhalation administion of nitroglycerin is the only practicable solution open to the patient for treating the attack, since this active substance can take an immediate effect on account of its physiochemical properties and its special pharmacological profile.
Since the specialist has hitherto not made therapeutic use of the immediate onset of action of calcium antagonists, in the knowledge of the strong peripheral effect of this active substance class, practically only nitroglycerin remained for treating acute cases, but with nitroglycerin one has to reconcile to side-effects such as nausea, dizziness, tachycardia, and a sudden drop in blood pressure.
It has surprisingly been found that calcium-antagonists are immediately effective upon inhalational administration and cause an immediate increase in the blood flow in the coronary artery without exerting an unfavorable influence on the periphery.
Thus calcium-antagonists are unexpectedly suitable for therapy of angina pectoris attacks when administered by inhalation. They have the great advantage as compared with the therapy known hitherto that the side-effects of nitroglycerin are avoided and the described activity of calcium-antagonists, which are concededly drugs of first choice in influencing the pathophysiological condition, can also be made use of in acute attacks.